Endovascular apparatus for perfusing organs in a body

ABSTRACT

In one representative embodiment, a method of perfusing organs in a patient&#39;s body is provided. The method comprises isolating the visceral arteries and the visceral veins from blood circulating through the patient&#39;s heart and perfusing the visceral arteries, the visceral veins, and the abdominal organs with a perfusion fluid that is fluidly separated from the blood circulating through the patient&#39;s heart. While the visceral arteries and the visceral veins are isolated, and the visceral arteries, the visceral veins, and the abdominal organs are being perfused, the patient&#39;s blood is allowed to continue to circulate through the heart.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/397,704, filed Apr. 29, 2019, which is a continuation of U.S.National Stage application Ser. No. 15/115,623, filed Jul. 29, 2016,issued as U.S. Pat. No. 10,278,384 on May 7, 2019, which is the U.S.National Stage of International Application No. PCT/US2014/068116, filedDec. 2, 2014, which claims the benefit of and priority to U.S.Provisional Application No. 61/935,729, filed Feb. 4, 2014; each of theprior applications are incorporated by reference herein in theirentirety.

FIELD

The present application concerns embodiments of an endovascularapparatus for perfusing organs in a patient, such as an organ donorpatient until the organs can be removed for transplant.

BACKGROUND

In the U.S., over 120,000 patients are in need of an organ transplant.It has been reported that only about 28,000 people received organtransplants organs in 2012 in the U.S. As a result, an average of 18patients will die each day awaiting an organ transplant. Furthermore,the economic burden of kidney dialysis while awaiting transplant issignificant, costing nearly S40 billion dollars a year in the U.S.alone.

Organs recovered from living donors and those donated after brain death(DBD) (also referred to as “heartbeating donation” (HBD)) representcontrolled situations where organs can be carefully exposed and cooledimmediately at the time of recovery. This rapid cooling allows thehighest preservation of function. Donation after cardiac death (DCD)(also referred to as “non-heartbeating donation” (NHBD)) represents agrowing source of organs but presents unique challenges with regard toadequately preserving organ function just prior to transplant.

Organs (e.g., kidneys) from all donor types are susceptible to warmischemia, which is caused by reduced blood flow or the cessation ofblood flow to organs and can result in significant loss of organfunction. DCD donors are particularly susceptible to rather long warmischemia times compared to DBD donors because DCD donors can experiencerelatively long periods of low blood pressure that is inadequate fororgan perfusion prior to actual cardiac death, such as after the DCDdonor is removed from life support. Needless to say, maneuvers thatexpedite cardiac death are prohibited. Moreover, in order to ensure thatbrain damage after cardiac arrest is irreversible, transplant teams mustwait a predetermined time period prior to commencing the procedure forremoving an organ from the DCD donor. This time period typically isreferred to as a “no-touch” time period and on average is at least fiveminutes from the time of pronounced cardiac death. Consequently, warmischemia times of about 10-40 minutes have been documented for DCDdonors. As a result of these delays, warm ischemia can result insignificant loss of organ function.

SUMMARY

The present disclosure concerns embodiments of an endovascular apparatusthat can be used to perfuse the organs of a patient, for example, theorgans of a donor patient until the organs can be explanted, therebyminimizing warm ischemia times. In particular embodiments, theendovascular apparatus is configured to isolate blood circulatingthrough the heart from flowing through the visceral arteries and veinswhile perfusing the organs within the abdomen with a separate perfusionliquid that helps preserve organ function until explant. As such, theendovascular apparatus is particularly suited for maintaining adequateperfusion of organs in DCD donors, in which there may not be adequateblood flow to the abdominal organs prior to cardiac arrest and duringthe so called “no-touch” time period following cardiac arrest. Thedisclosed methods and apparatuses therefore can significantly increasethe number of viable organs that can be made available for transplant.In alternative embodiments, the disclosed methods and apparatuses canalso be used to perfuse organs in survival surgery, such as cardiac orproximal aortic repairs where prolonged cessation of blood flow poses arisk of organ damage.

In one representative embodiment, a method of perfusing organs in apatient's body is provided. The method comprises isolating the visceralarteries and the visceral veins from blood circulating through thepatient's heart. The visceral arteries, the visceral veins, and theabdominal organs are perfused with a perfusion fluid that is fluidlyseparated from the blood circulating through the patient's heart. Whilethe visceral arteries and the visceral veins are isolated and beingperfused with a perfusion fluid, the patient's blood continues tocirculate through the heart and other parts of the body.

In another representative embodiment, a method of perfusing organs in apatient's body comprises deploying a first perfusion stent in thepatient's aorta and a second perfusion stent in the patient's vena cava,the first perfusion stent allowing blood from the heart to flow in adownstream direction from a location upstream of the abdominal organs toa location downstream of the abdominal organs without flowing into thevisceral arteries, the second perfusion stent allowing blood to flow ina downstream direction from a location upstream of the abdominal organsto a location downstream of the abdominal organs without flowing intothe visceral veins. The first perfusion stent has enlarged end portionsthat seal against the inner wall of the aorta and an intermediateportion defining an arterial perfusion space between the inner wall ofthe aorta and the outer surface of the intermediate portion, and thesecond perfusion stent has enlarged end portions that seal against theinner wall of the vena cava and an intermediate portion defining avenous perfusion space between the inner wall of the vena cava and theouter surface of the intermediate portion. The first perfusion conduithas an end portion that extends through one of the enlarged end portionsof the first perfusion stent; and the second perfusion conduit has anend portion that extends through one of the enlarged end portions of thesecond perfusion stent. The perfusion fluid flows through the firstperfusion conduit, through the arterial perfusion space, through thevisceral arteries, through the abdominal organs, through the visceralveins, through the venous perfusion space, and into the second perfusionconduit.

In another representative embodiment, a method of perfusing organs in apatient's body comprises inserting an arterial catheter into thepatient's aorta and inserting a venous catheter into the patient's venacava. The arterial catheter has a first lumen, a second lumen, and firstand second balloons spaced apart along the length of the arterialcatheter. The venous catheter has a first lumen, a second lumen, andfirst and second balloons spaced apart along the length of the venouscatheter. The method further comprises positioning the arterial catheterin the aorta such that the first balloon is upstream of the visceralarteries and the second balloon is downstream of the visceral arteries,and positioning the venous catheter in the vena cava such that the firstballoon is upstream of the visceral veins and the second balloon isdownstream of the visceral veins. The first and second balloons of thearterial and venous catheters are inflated, thereby isolating thevisceral arteries and visceral veins from blood circulating through thepatient's heart. A flow of a perfusion fluid flows into and through thesecond lumen of the arterial catheter, into and through the visceralarteries, the abdominal organs, and the visceral veins, and into andthrough the second lumen of venous catheter while blood from the heartis allowed to flow into and through the first lumen of the arterialcatheter, and back into and through the first lumen of the venouscatheter.

In another representative embodiment, an assembly for perfusing organsin a patient's body comprises a first perfusion stent, a secondperfusion stent, a source of a perfusion fluid, a first perfusionconduit, and a second perfusion conduit. The first perfusion stent isconfigured to be deployed within the aorta of a patient, the firstperfusion stent allowing blood from the heart to flow in a downstreamdirection from a location upstream of the abdominal organs to a locationdownstream of the abdominal organs without flowing into the visceralarteries. The second perfusion stent is configured to be deployed withinthe vena cava of the patient, the second perfusion stent allowing bloodto flow in a downstream direction from a location upstream of theabdominal organs to a location downstream of the abdominal organswithout flowing into the visceral veins. The first perfusion conduit hasan inlet in fluid communication with the source of the perfusion fluidand an outlet that is configured to be in fluid communication with thevisceral arteries when the first perfusion stent is deployed within theaorta. The second perfusion conduit has an inlet that is configured tobe in fluid communication with the visceral veins when the secondperfusion stent is deployed within the vena cava. Using the assembly,perfusion fluid can flow through the first perfusion conduit, throughthe arterial perfusion space, through the visceral arteries, through theabdominal organs, through the visceral veins, through the venousperfusion space, and into the second perfusion conduit.

In another representative embodiment, an assembly for perfusing organsin a patient's body comprises an arterial catheter configured to beinserted into the aorta of a patient. The arterial catheter comprises afirst lumen, a second lumen, and first and second balloons spaced apartalong the length of the arterial catheter. The balloons are configuredto seal against the inner wall of the aorta upstream and downstream ofthe visceral arteries to isolate the visceral arteries from bloodcirculating through the patient's heart. The assembly further comprisesa venous catheter configured to be inserted into the vena cava of apatient. The venous catheter comprises a first lumen, a second lumen,and first and second balloons spaced apart along the length of thevenous catheter. The balloons are configured to seal against the innerwall of the vena cava upstream and downstream of the visceral veins toisolate the visceral veins from blood circulating through the patient'sheart. A source of a perfusion fluid is in fluid communication with thesecond lumen of the arterial catheter. The first lumen of the arterialcatheter is in fluid communication with the first lumen of the venouscatheter to allow blood from the heart to flow into and through thefirst lumen of the arterial catheter, and back into and through thefirst lumen of the venous catheter.

In another representative embodiment, a perfusion stent implantablewithin a body lumen is provided. The perfusion stent comprises aradially compressible and expandable, elongated body comprising firstand second end portions and an intermediate portion extending from thefirst end portion to the second end portion. The first and second endportions have an outer diameter greater than an outer diameter of theintermediate portion when the body is in a radially expanded state,thereby defining an annular perfusion space between the first and secondend portions and around the intermediate portion. The perfusion stentalso comprises a central lumen extending through the first end portion,the intermediate portion, and the second end portion, and a perfusionlumen extending at least partially through the first end portion andhaving a distal opening in communication with the perfusion space. Whenthe elongated body is in the radially expanded state within the bodylumen, and the first and second end portions are engaged with an innerwall of the body lumen, the central lumen is fluidly separated from theperfusion space. In another representative embodiment, the perfusionfluid being circulated through the isolated visceral arteries, visceralveins and abdominal organs is the patient's own blood. This blood is ina fluidly separate circuit from the blood being circulated by the heart.The blood perfusing the isolated visceral arteries, visceral veins andabdominal organs can flow into and through the second lumen of thearterial catheter, into and through the visceral arteries, the abdominalorgans, and the visceral veins, and into and through the second lumen ofvenous catheter. The venous effluent (blood from the venous catheter)can be warmed, oxygenated and/or pressurized by an external device andreturned to the second lumen of the arterial catheter to repeat thecycle. Meanwhile, blood from the heart is allowed to flow into andthrough the first lumen of the arterial catheter, and back into andthrough the first lumen of the venous catheter. This provides theabdominal organs with warmed, pulsatile, oxygenated blood independent ofthe blood being circulated by the heart.

The foregoing and other features and advantages of this disclosure willbecome more apparent from the following detailed description of severalembodiments which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary embodiment of an endovascular apparatusfor perfusing organs of a patient.

FIG. 2 is an enlarged view of the apparatus of FIG. 1 , showing theapparatus deployed within the body of a patient.

FIG. 3 is a cross-section view of the apparatus of FIG. 2 taken alongline 3-3 of FIG. 2 .

FIG. 4 is a cross-section view of the apparatus of FIG. 2 taken alongline 4-4 of FIG. 2 .

FIG. 5 illustrates another exemplary embodiment of an endovascularapparatus for perfusing organs of a patient.

FIG. 6 is a side view of an arterial catheter of an endovascularapparatus, according to another embodiment.

FIG. 7 is a cross-section view of the apparatus of FIG. 6 taken alongline 7-7 of FIG. 6 .

FIG. 8 is a cross-section view of the apparatus of FIG. 6 taken alongline 8-8 of FIG. 6 .

FIG. 9 illustrates another exemplary embodiment of an endovascularapparatus for perfusing organs of a patient.

FIG. 10 illustrates an endovascular apparatus for perfusing organs of apatient, according to another embodiment.

FIG. 11 is an enlarged view of the apparatus of FIG. 10 , showing theapparatus deployed within the body of a patient.

FIG. 12 is a side view of an annular frame of a perfusion stent,according to one embodiment.

FIG. 13 is a side view of a perfusion stent, according to oneembodiment.

FIG. 14 is a cross-section view of the perfusion stent of FIG. 13 takenalong line 13-13 of FIG. 14 .

FIG. 15 is a cross-section view of the perfusion stent of FIG. 13 takenalong line 14-14 of FIG. 15 .

FIG. 16 is a cross-section view of the perfusion stent of FIG. 13 takenalong line 15-15 of FIG. 16 .

FIG. 17 shows a delivery apparatus being used to deliver a perfusionstent within the aorta of a patient.

FIG. 18 illustrates an exemplary embodiment of an endovascular apparatusfor perfusing organs of a patient, according to another embodiment,

DETAILED DESCRIPTION

The present disclosure concerns embodiments of an endovascular apparatusthat can be used to perfuse the organs of a patient, such as an organdonor patient until the organs can be removed, thereby minimizing warmischemia times. In particular embodiments, the endovascular apparatus isconfigured to isolate blood from the heart from flowing through thevisceral arteries and veins while perfusing the organs within theabdomen with a separate perfusion liquid that helps preserve organfunction until explant. As such, the endovascular apparatus isparticularly suited for maintaining adequate perfusion of organs in DCDdonors, in which there may not be adequate blood flow to the abdominalorgans prior to cardiac arrest and during the so called “no-touch” timeperiod following cardiac arrest.

Referring first to FIGS. 1 and 2 , there is shown an endovascularapparatus 10 for isolating and perfusing the organs of a patient (e.g.,an organ donor patient), according to one embodiment. The apparatus 10in the illustrated embodiment comprises a first, arterial catheter 12and a second, venous catheter 14. The arterial catheter 12 is configuredto isolate the visceral arteries 80 and divert blood from the aorta 82to a location outside the body while the venous catheter 14 isconfigured to isolate the visceral veins 84 and introduce the blood backinto the inferior vena cava 86 of the patient. The arterial catheter 12also is configured to introduce a perfusion fluid (e.g., a coldperfusion solution) into the visceral arteries 80 for the purpose ofperfusing donor organs (e.g., kidneys 114 or liver 116) in the abdominalcavity until such time the organs can be explanted. The venous catheter14 also is configured to be placed into fluid communication with thevisceral veins 84 in order to remove the perfusion fluid from the body.

The arterial catheter 12 in the illustrated embodiment comprises a firstshaft 16 defining a first lumen 54 (FIG. 3 ) and a second shaft 18defining a second lumen 60 (FIG. 3 ). Mounted on the shafts 16, 18 is adistal balloon 20 and a proximal balloon 22 spaced from the distalballoon 20. As shown in FIGS. 1 and 2 , the first and second shafts 16,18 extend through the proximal balloon 22. The first shaft 16 can extendthrough the distal balloon 20 and has a distal opening 24 that is influid communication with the aorta upstream of the distal balloon. Thesecond shaft 18 can terminate at a location proximal to the distalballoon 20 and can have a closed end 26. The second shaft 18 also canhave one or more side openings, or apertures, 28 along the length of theshaft between the distal and proximal balloons 20, 22, respectively. Asbest shown in FIG. 2 , a proximal end portion 30 of the second shaft 18can be fluidly connected to a source 32 of a perfusion fluid. A proximalend portion 33 of the first shaft 16 can be fluidly connected to aninlet port of a blood warmer 34.

The venous catheter 14 in the illustrated embodiment comprises a firstshaft 36 defining a first lumen 62 (FIG. 4 ) and a second shaft 38defining a second lumen 68 (FIG. 4 ). Mounted on the shafts 36, 38 is adistal balloon 40 and a proximal balloon 42 spaced from the distalballoon 40. As shown in FIGS. 1 and 2 , the first and second shafts 36,38 extend through the proximal balloon 42. The first shaft 36 can extendthrough the distal balloon 40 and has a distal opening 44 that is influid communication with the inferior vena cava downstream of the distalballoon. The second shaft 38 can terminate at a location proximal to thedistal balloon 40 and can have a closed end 46. The second shaft 38 alsocan have one or more side openings, or apertures, 48 along the length ofthe shaft between the distal and proximal balloons 40, 42, respectively.As best shown in FIG. 2 , a proximal end portion 50 of the second shaft38 can extend outside the body for draining perfusion fluid away fromthe body. A proximal end portion 52 of the first shaft 36 can be fluidlyconnected to an outlet port of the blood warmer 34.

As shown in FIG. 3 , the first shaft 16 of the arterial catheter 12 canhave a first lumen 54 for diverting blood from the aorta to the bloodwarmer 34 and second and third lumens, 56, 58, respectively, forintroducing an inflation fluid to the distal and proximal balloons 20,22, respectively. The second lumen 56 can have a distal end in fluidcommunication with the inside of the distal balloon 20 and a proximalend in fluid communication with a source of an inflation fluid (notshown). The third lumen 58 can have a distal end in fluid communicationwith the inside of the proximal balloon 22 and a proximal end in fluidcommunication with the source of the inflation fluid. Thus, in use, aninflation fluid (e.g., saline) can be introduced under pressure into theballoons to inflate the balloons and cause them to engage and form aseal with the inner wall of the aorta. The second shaft 18 can have alumen 60 that allows a perfusion fluid from the source 32 to beintroduced into the visceral arteries 80. In an alternative embodiment,the inflation lumens 56, 58 can be provided in the second shaft 18rather than in the first shaft 16. In another embodiment, one of theinflation lumens can be provided in the first shaft 16 and the otherinflation lumen can be provided in the second shaft 18.

As shown in FIG. 4 , the first shaft 36 of the venous catheter 14 canhave a first lumen 62 for introducing blood from the blood warmer 34back into the body and second and third lumens, 64, 66, respectively,for introducing an inflation fluid to the distal and proximal balloons40, 42, respectively. The second lumen 64 can have a distal end in fluidcommunication with the inside of the distal balloon 40 and a proximalend in fluid communication with the inflation fluid source. The thirdlumen 66 can have a distal end in fluid communication with the inside ofthe proximal balloon 42 and a proximal end in fluid communication withthe inflation fluid source. Thus, in use, an inflation fluid (e.g.,saline) can be introduced under pressure into the balloons 40, 42 toinflate the balloons and cause them to engage and form a seal with theinner wall of the inferior vena cava. The second shaft 38 can have alumen 68 that allows the perfusion fluid returning from the visceralveins 84 to flow outside the body, where it can be collected anddisposed of as waste. In an alternative embodiment, the inflation lumens64, 66 can be provided in the second shaft 38 rather than in the firstshaft 36. In another embodiment, one of the inflation lumens can beprovided in the first shaft 36 and the other inflation lumen can beprovided in the second shaft 38.

Each of the catheters 12, 14 can include suitable positioning markersand/or sensors at convenient locations to assist in locating theballoons of each catheter at the desired locations within the aorta andthe inferior vena cava. In the illustrated embodiment, for example, thefirst shaft 16 of the arterial catheter 12 includes a pair of radiopaquemarkers 68 aligned with the distal and proximal balloons 20, 22,respectively. Similarly, the first shaft 36 of the venous catheter 14includes a pair of radiopaque markers 68 aligned with the distal andproximal balloons 40, 42, respectively. In alternative embodiments, themarkers 68 can be provided on the second shafts 18, 38 or on both thefirst and second shafts of each catheter 12, 14. Also, although theillustrated embodiment includes a pair of markers 68 for each catheter,a greater or fewer number of markers can be provided for each catheter12, 14.

In alternative embodiments, the positioning markers can comprise passiveor active emitters that can emit electromagnetic waves through the bodyand a corresponding detector or monitor can be used to receive theelectromagnetic waves from the emitters and provide visual and/oraudible feedback to a user indicating the position of the markers insidethe body relative to external landmarks on the body. In particularembodiments, for example, the positioning markers can be emitters thatcan emit radiofrequency waves, such as radiofrequency identification(RFID) tags. Further details of the use of RFID tags as positioningmarks are disclosed in co-pending Application No. 61/845,896, filed Jul.12, 2013, and PCT/US2014/046224, filed Jul. 10, 2014, which areincorporated herein by reference.

In use, as depicted in FIG. 1 , the first catheter 12 can be insertedinto the aorta via an incision in a femoral artery in a minimallyinvasive manner using known techniques. Similarly, the second catheter14 can be inserted into the inferior vena cava via an incision in afemoral vein in a minimally invasive manner Guidewires, dilators and/orintroducers can be used to help introduce and advance the cathetersthrough the patient's vasculature, as known in the art. As best shown inFIG. 2 , the arterial catheter 12 is positioned such that the distalballoon 20 is upstream of the visceral arteries 80 and the proximalballoon 22 is downstream of the visceral arteries 80. Similarly, thevenous catheter 14 is positioned such that the distal balloon 40 isdownstream of the visceral veins 84 and the proximal balloon 42 isupstream of the visceral veins 84. The proper positioning of thecatheter 12, 14 can be accomplished by viewing the markers 68 underfluoroscopy.

Once the catheters are in place, each pair of balloons can be inflatedagainst the inner walls of the aorta and inferior vena cava, therebyisolating the visceral arteries and veins. This causes oxygenated bloodfrom the heart to flow through the first shaft 16 of the arterialcatheter, through the blood warmer, through the first catheter 36 of thevenous catheter and into the inferior vena cava where blood can flowback into the right atrium of the heart, as indicated by arrows 90. Atthe same time, a cold perfusion fluid from source 32 is introduced intothe visceral arteries 80 via the side openings 28 in the second shaft 18of the arterial catheter, as indicated by arrows 92. The perfusion fluidcan flow through the abdominal organs, the visceral veins 84 and intothe isolated region of the inferior vena cava, where it can then flowinwardly through the side openings 48 of the second catheter 38, asindicated by arrows 94. The perfusion fluid can then be removed from thebody via the second catheter 38 for proper disposal.

In particular embodiments, the perfusion fluid can be similar to theUniversity of Wisconsin solution and can comprise, without limitation,one or more of the following compounds: heparin, pentastarch, steroids,lactobionic acid, magnesium sulfate, raffinose, adenosine, allopurinol,glutathione, and potassium hydroxide. The perfusion fluid can be cooledto a temperature of about 0 degree C. to about 10 degrees C. forintroduction into the body and more preferably to a temperature of about4 degrees C. to about 6 degrees C. As an alternative perfusion fluid,blood separate from the circuit of blood being circulated by the heartcan be propelled, oxygenated and warmed before being cycled continuouslythrough the catheters, as further described below.

As noted above, the apparatus is particularly suited for use with DCDdonors. In this regard, the catheters 12, 14 can be inserted anddeployed (i.e., the balloons inflated to isolate the visceral arteriesand veins) in the vasculature of a DCD donor as soon as possible priorto cardiac death. For example, the catheters 12, 14 can be inserted anddeployed in a DCD donor just prior to or at the same time as removingthe patient from life support or when the donor is experiencing unstablevital signs for normal organ blood flow. The blood flow circuit allowsfor normal blood flow through the body, except for those isolatedregions, while awaiting expected cardiac death and during thepredetermined waiting period before explant can occur. In anotherimplementation, the catheters 12, 14 can be inserted into the DCD donorprior to cardiac death and then are deployed at the time of cardiacdeath. In yet another implementation, the apparatus can be inserted anddeployed in a donor who expires prematurely before a donor team is readyto perform the explant procedure. In any case, during the period of timebefore explant can be performed, the perfusion fluid reduces warmischemia time and preserves organ function.

In another embodiment, the catheters 12, 14 can be inserted into theaorta and the vena cava of a donor (e.g., a DCD donor) but not deployed(i.e., the balloons are not inflated) until after cardiac death or untilafter the predetermined waiting period. This allows for normal bloodflow throughout the body until the balloons are deployed. At theprescribed time (e.g., after confirmed cardiac death), the balloons canbe rapidly deployed to isolate the visceral arteries and veins and aperfusion fluid (e.g., a cold solution or blood) can be circulatedthrough the isolated regions until explant.

In the embodiment of FIGS. 1 and 2 , the catheters 12, 14 also isolatethe lower extremities from the flow of blood. It has been found thathumans can tolerate lower extremity ischemia for several hours. Ifdesired, however, the apparatus 10 can be adapted to permit blood fromthe heart to circulate through the lower extremities.

For example, FIG. 5 shows the apparatus 10 of FIGS. 1 and 2 withadditional components to permit blood from the heart to circulatethrough the lower extremities. In the embodiment of FIG. 5 , theapparatus 10 further includes an arterial extension portion or conduit100 that has a first end portion 102 that is in fluid communication withthe proximal end portion 33 of the first shaft 16 of the arterialcatheter 12. A second end portion 104 of the extension portion 100 canbe inserted into a femoral artery, which can be the same femoral arterythrough which the arterial catheter 12 has been inserted or the otherfemoral artery. If the extension portion 100 is inserted into the samefemoral artery as the arterial catheter 12, the extension portion 100would be inserted downstream of the insertion point of the arterialcatheter 12. The conduit 100 diverts a portion of blood from shaft 16 toflow into the vasculature of the lower extremities.

In the embodiment of FIG. 5 , the apparatus 10 also includes a lowerextremity return line or conduit 106 having a first end portion 108inserted into a femoral vein, which can be the same femoral vein throughwhich the venous catheter 14 has been inserted or the other femoralvein. If the return conduit 106 is inserted into the same femoral veinas the venous catheter 14, the return line would be inserted upstream ofthe insertion point of the venous catheter 14. A second end portion 110of the return conduit 106 is in fluid communication with an inlet portof a blood pump 112. As shown in FIG. 5 , the proximal end portion 33 ofshaft 16 is also in fluid communication with a respective inlet port ofthe blood pump 112. In this manner, the blood flowing through thevasculature of the lower extremities is returned to pump 112 via thereturn conduit 106.

The blood pump 112 is configured to allow higher pressure blood fromshaft 16 and lower pressure blood from return conduit 106 to mix andequalize before it is pumped under pressure into shaft 36 of the venouscatheter 14. For example, the blood pump can have an internal storagechamber that receives blood from the return conduit 106 and shaft 16 atstatic pressure. Blood from the storage chamber can then be pumped underpressure into shaft 36. In this manner, blood from the heart can bediverted to flow through the lower extremities and back into the venacava. Blood from shaft 16 and return conduit 106 can also flow through ablood warmer, which can be an integral or separate component from theblood pump 112.

FIG. 6 shows an arterial catheter 200 for an endovascular apparatus,according to another embodiment. The arterial catheter 200 performs thesame function as the arterial catheter 12 of FIGS. 1 and 2 but has adifferent construction. The arterial catheter 200 comprises an outershaft 202, an inner shaft 204 spaced radially inwardly from the outershaft 202, an annular lumen 206 defined between shafts 202, 204, and aninner lumen 208 defined by the inner shaft 204. Mounted on the outershaft 202 are two spaced apart inflatable balloons 210, 212. A pluralityof side openings or apertures 214 are formed along the length of theouter shaft 202 between the balloons 210, 212. First and secondinflation conduits 216, 218, respectively, extend through the annularlumen 206. The first inflation 216 conduit has a distal end that isfluid communication with the proximal balloon 212 and a proximal endthat is in fluid communication with a source of an inflation fluid. Thesecond inflation conduit 218 has a distal end that is fluidcommunication with the distal balloon 214 and a proximal end that is influid communication with the inflation fluid source.

The proximal end of the outer shaft 202 can terminate at a proximal hub220 that extends outside the body and is fluidly connectable to a sourceof a perfusion fluid. The inner shaft 204 has a proximal end portion 222that extends outside the body and is fluidly connectable to a bloodwarmer and/or pump (not shown in FIG. 6 ). The annular lumen 206 isclosed at the distal end of the outer shaft 202.

The arterial catheter 200 can be inserted and deployed within apatient's aorta in the same manner described above in connection withthe arterial catheter 12. A venous catheter (not shown) having the sameconstruction as the arterial catheter 200 can be inserted into the venacava in the same manner described above in connection with the venouscatheter 14. In use, the inner shaft of the venous catheter is fluidlyconnected to the outlet of the blood pump/warmer and the outer shaft ofthe venous catheter can be fluidly connected to a drain outside thebody. Upon deployment of the arterial catheter 200 and the similarlyconstructed venous catheter, the visceral arteries and veins areisolated and blood from the heart flows proximally through the innerlumen 208 and exits the body where it can be routed through the bloodpump/warmer, as indicated by arrows 224. Blood from the bloodpump/warmer can be returned to the vena cava via the inner lumen of thevenous catheter where returning blood can flow back to the heart. Theabdominal organs can be perfused by introducing a pressurized perfusionfluid into the annular lumen 206 of the catheter 200, which then flowsoutwardly through side openings 214 into the visceral arteries. Theperfusion fluid can then flow through the abdominal organs, the visceralveins, and back into and through the annular lumen of the venouscatheter via side openings in the venous catheter.

FIG. 9 shows an endovascular apparatus 300, according to anotherembodiment. The apparatus 300 is similar in many respects to theapparatus 10 of FIGS. 1 and 2 . Thus, components in FIG. 9 that are thesame as components in FIGS. 1 and 2 are given the same respectivereference numbers and are not described further.

In the embodiment of FIG. 9 , the isolated regions of the patient'svasculature can be perfused with the patient's own blood rather than acold perfusion solution. The apparatus 300 comprises a cardiopulmonarybypass machine 302 or equivalent device that can warm, oxygenate andpressurize blood. The machine 302 has an inlet port fluidly connected tothe second shaft 38 of the venous catheter 14 and an outlet port fluidlyconnected to the second shaft 18 of the arterial catheter. In use, bloodcan be drawn from the patient and introduced into a blood flow circuitthat is fluidly separated from the blood being circulated by the heart.The blood being used as the perfusion fluid is circulated outwardly fromthe body via the second shaft 38 of the venous catheter 14, and throughthe cardiopulmonary bypass machine 302, which can oxygenate and warm theblood, and pump the blood back into the body via the second shaft 18 ofthe arterial catheter 12, in the direction indicated by arrows 304.Maintaining blood circulation through the isolated regions that isfluidly separated from the circulation of blood through the patient'sheart allows for adequate perfusion of the organs while awaiting cardiacdeath.

The embodiments disclosed herein can be used for procedures other thanprocedures for preserving organ function for explant surgery. Forexample, in another implementation, an endovascular apparatus (e.g., anapparatus of FIG. 1, 5 or 6 ) can be used to perfuse organs duringsurvival surgery, such as cardiac or proximal aortic repairs whereprolonged cessation of blood flow poses a risk of organ damage.

Referring to FIGS. 10 and 11 , there is shown another embodiment of anendovascular apparatus that can be used for isolating and perfusing theorgans of a patient (e.g., an organ donor patient), indicated generallyat 400. The apparatus 400 in the illustrated embodiment comprises anarterial perfusion stent 402 and a venous perfusion stent 404. Thearterial perfusion stent 402 is configured to isolate blood flow to thevisceral arteries 80, while allowing blood from the aorta 82 to continueto flow to the lower extremities. The venous perfusion stent 404 isconfigured to isolate blood flow from the visceral veins 84, whileallowing blood from the lower extremities to continue to flow to theheart via the inferior vena cava 86 of the patient. Thus, when deployedin a patient, the endovascular apparatus allows blood from the heart topass uninterrupted through a central lumen of the arterial perfusionstent 402 to perfuse the lower body and then flow through a centrallumen of the venous perfusion stent 404 to return to the heart.

Additionally, the arterial perfusion stent 402 of endovascular apparatus400 is configured to introduce a perfusion fluid (e.g., a cold perfusionsolution, or re-oxygenated and/or warmed blood) into the visceralarteries 80 for the purpose of perfusing donor organs (e.g., kidneys 114or liver 116) in the abdominal cavity until such time the organs can beexplanted. The venous perfusion stent 404 is configured to receive theperfusion fluid from the visceral veins 84 that was introduced into thebody from the arterial perfusion stent 402. As discussed in more detailbelow, the arterial and venous perfusion stents 402, 404 can eachcomprise a perfusion lumen (such as defined by an arterial perfusionconduit or sleeve 446 and a venous perfusion conduit or sleeve 448, seeFIG. 11 ) that facilitates perfusion of blood or fluid through theabdominal organs, while allowing normal blood flow between the heart andlower extremities. Additionally, the arterial and venous perfusionstents 402, 404 include a non-porous liner 466 (best shown in FIG. 13 )that prevents or substantially reduces mixing of blood or other fluidsflowing through the aorta or inferior vena cava and the visceralarteries and veins.

The arterial perfusion stent 402 comprises an elongated body thatincludes a radially compressible and expandable annular frame 430supporting the liner 466. In FIG. 13 the frame 430 comprise a metalmesh, although the frame can have other configurations in otherembodiments. Referring to FIGS. 13-16 , in the illustrated embodiment,the stent 402 defines a central lumen 403 that extends from a proximalend 408 to a distal end 406 of the perfusion stent. The central lumen403 allows passage of fluid (e.g., blood) through the body of theperfusion stent, thus maintaining blood flow through the artery in whichthe perfusion stent is deployed. The perfusion stent 402 can be radiallycompressible to a compressed state for delivery through the body to adeployment site and expandable to its functional size shown in FIG. 11at the deployment site. In certain embodiments, the perfusion stent 402is self-expanding; that is, the stent can radially expand to itsfunctional size when advanced from the distal end of a delivery sheath.Apparatuses particularly suited for percutaneous delivery andimplantation of a self-expanding stent in the vessels of the body arewell known and described briefly below. In other embodiments, theperfusion stent can be a plastically-expandable perfusion stent that canbe adapted to be mounted in a compressed state on the balloon of adelivery catheter or another type of expansion device configured toexpand the stent radially from a compressed delivery state to a radiallyexpanded state. The perfusion stent can be expanded to its functionalsize at a deployment site by inflating the balloon of a ballooncatheter, as known in the art.

The elongated body of the arterial perfusion stent 402 comprises adistal end portion 410, a generally cylindrical intermediate portion412, and a proximal end portion 414. The distal end portion 410 cancomprise a generally cylindrical first section 411 a and a taperedsecond section 411 b positioned proximal to the first section 411 a.Likewise, the proximal end portion 414 can comprise a generallycylindrical first section 415 a and a tapered second section 415 bproximal to the first section 415 a. In the radially expanded state ofthe perfusion stent, the distal and proximal end portions 410, 414 havean outer diameter that is larger than the outer diameter of theintermediate portion 412, thereby defining an annular perfusion space416 (best shown in FIG. 11 ) between the end portions and around theintermediate portion. Central lumen 403 extends through body of thearterial perfusion stent, allowing flow of fluid (e.g., blood) throughfrom the distal end 406 to the proximal end 408 of the arterialperfusion stent, in the direction of arrows 415 shown in FIG. 11 .

The outer surfaces of the distal and proximal end portions 410, 414 forma seal against the inner wall of the aorta when the arterial perfusionstent is in the radially expanded state. Thus, the outer surface of thedistal and proximal end portions 410, 414 of the stent in the radiallyexpanded state can have a diameter that is about the diameter of theinner surface in the region of the aorta where the stent will be placed.For example, for a perfusion stent to be placed in an adult, the outersurface of the distal and proximal end portions 410, 414 of the stent inthe radially expanded state can have a diameter ranging from 12 mm to 3cm. Smaller stents can be used in pediatric patients.

The venous perfusion stent 404 can have the same construction as thearterial perfusion stent 402. Thus, in the illustrated embodiments, thevenous perfusion stent 404 has a distal end 418 and a proximal end 420.The stent 404 can comprise a distal end portion 422, a generallycylindrical intermediate portion 424, and a proximal end portion 426.The distal end portion 422 can comprise a generally cylindrical firstsection 423 a and a tapered section 423 b positioned proximal to thefirst section 423 a. Likewise, the proximal end portion can comprise agenerally cylindrical first section 427 a and a tapered second section472 b positioned proximal to the first section 427 a. In the radiallyexpanded state of the venous perfusion stent, the distal and proximalend portions 422, 426 have an outer diameter that is larger than theouter diameter of the intermediate portion 424, thereby defining anannular perfusion space 428 (best shown in FIG. 11 ) between the endportions and around the intermediate portion. A central lumen extendsthrough body of the venous perfusion stent, allowing flow of fluid(e.g., blood) through from the proximal to distal end of the venousperfusion stent, in the direction of arrows 427 shown in FIG. 11 .

The outer surfaces of the distal and proximal end portions 422, 426 formseals against the inner wall of the inferior vena cava when the venousperfusion stent is in the radially expanded state. Thus, the outersurface of the distal and proximal end portions 422, 426 of the stent inthe radially expanded state can have a diameter that is about thediameter of the inner surface in the region of the inferior vena cavawhere the stent will be placed. For example, for a perfusion stent to beplaced in an adult, the outer surface of the distal and proximal endportions 422, 426 of the stent in the radially expanded state can have adiameter ranging from 15 mm to 3 cm. Smaller stents can be used inpediatric patients.

FIG. 12 shows an alternate embodiment of an expandable annular frameindicated generally at 500 that can be used for the perfusion stent 402or the perfusion stent 404. As shown, the frame 500 has a distal end 502and a proximal end 504. The frame 500 can comprise an enlarged distalend portion 506, a generally cylindrical intermediate portion 508, andan enlarged proximal end portion 510. In the radially expanded state ofthe perfusion stent, the distal and proximal end portions 506, 510 havean outer diameter that is larger than the outer diameter of theintermediate portion 508. The intermediate portion 508 can be formedfrom a plurality of longitudinally extending frame members, or struts,512. The distal and proximal end portions 506, 510 can be formed fromangled struts 514 that are welded or otherwise secured to each other atnodes 516 formed from the vertices of adjacent bends so as to form amesh structure.

The struts 512, 514 of the distal, intermediate, and proximal portionsof the perfusion stent can be made of a suitable shape memory material,such as the nickel titanium alloy known as Nitinol, that allows theprosthetic valve to be compressed to a reduced diameter for delivery ina delivery apparatus (such as described below) and then causes theperfusion stent to expand to its functional size inside the patient'sbody when deployed from the delivery apparatus. If the perfusion stentis a balloon-expandable perfusion stent that is adapted to be crimpedonto an inflatable balloon of a delivery apparatus and expanded to itsfunctional size by inflation of the balloon, the perfusion stent 402 canbe made of a suitable plastically expandable material, such as stainlesssteel.

The distal, intermediate, and proximal portions 506, 508, 510 can beconstructed as a single unit, such as by machining (e.g., lasercutting). Alternatively, the frame can be constructed of separatesegments each comprising respective struts or frame members, and eachsegment can be welded or otherwise secured together using means known inthe art. In one example, the distal, intermediate, and proximal portions506, 508, 510 are each constructed separately and secured together.

As shown in FIG. 12 , the distal end portion 506 of the frame 500 in itsradially expanded state can have a cylindrical shape at its distalaspect and can gradually decrease in diameter to the diameter of theintermediate portion 508. The proximal end of the distal end portion ofthe frame 500 is secured to the distal end of the intermediate portion508 of the frame 430. The intermediate portion 508 of the frame in itsradially expanded state generally has a uniform cylindrical shape havinga diameter that is narrower than the outermost diameter of the distaland proximal end portions 436, 440 of the frame 500. The proximal end ofthe intermediate portion of the frame 500 is secured to the proximal endportion 510 of the frame 500. The proximal portion 510 of the frame 500in its radially expanded state can have a cylindrical shape at itsdistal aspect and can gradually decrease to a narrower diameter at itsproximal end, for example, to the diameter of the intermediate portion508. The tapered proximal sections of the distal end portion 506 and theproximal end portion 510 can facilitate re-sheathing and recapture ofthe stent, as further discussed below.

Although a particular shape for the frame 500 is shown in FIG. 12 , anyshape that allows for delivery of the perfusion stent to appropriatevessel location in the patient and for formation of a seal against theinner wall of the aorta and isolation of blood flow from the aorta tothe visceral arties can be used.

The venous perfusion stent 404 can also include an expandable annularframe, which can be substantially identical to frame 500 of the arterialperfusion stent. However, the frames of the arterial and venousperfusion stents 402, 404 can include minor structural differences (forexample in the diameter or length of the perfusion stent) as needed forthe placement and fit of the stents when implanted in to the aorta orinferior vena cava of the patient, respectfully.

Referring to FIG. 11 , the arterial perfusion stent 402 comprises aperfusion conduit 446 that facilitates perfusion of blood or otherperfusion fluid to the abdominal organs in the direction of arrows 452.The arterial perfusion conduit 446 comprises an outlet 447 that opensinto the arterial perfusion space 416. The perfusion fluid can flowthrough a perfusion lumen 450 (FIG. 16 ) of the arterial perfusionconduit 446 into the arterial perfusion space 416. The arterialperfusion conduit 446 can extend at least partially through the proximalend portion 414 of the stent body and has a proximal end that can extendbeyond the proximal end portion 414, where it can be fluidly connectedto a catheter 456 that extends outside of the body of the patient.Desirably, the catheter 456 can be connected to an oxygenator and/orblood warmer 458 and/or a blood pump 460. The oxygenator can add oxygento the blood or other fluid flowing through the catheter, and thepulsatile pump can push blood flow in the direction of arrow 461 throughthe endovascular apparatus 400 and the abdominal organs of the patient.

The arterial perfusion conduit 446 can be placed anywhere in the stentbody that allows the perfusion lumen 450 to be in fluid communicationwith the arterial perfusion space 416. In the illustrated embodiment,the arterial perfusion conduit extends from the interior of the proximalend portion 414 of the stent body to the arterial perfusion space 416,thereby allowing such access.

The venous perfusion stent 404 comprises a perfusion conduit 448 thatfacilitates perfusion of the perfusion fluid from the abdominal organsin the direction of arrows 462. The venous perfusion conduit 448comprises an inlet 449 at its distal end that opens into the venousperfusion space 428. The perfusion fluid can flow from the venousperfusion space 428 and into a perfusion lumen of the venous perfusionconduit 448. The venous perfusion conduit 448 can extend at leastpartially through the proximal end portion 426 of the stent body and hasa proximal end that can extend beyond the proximal end portion 426,where it can be connected to a catheter 464 that extends outside of thebody of the patient and connects to the blood pump 460 (as shown) and/orthe oxygenator and/or blood warmer 458.

The venous perfusion conduit 448 can be placed anywhere in the stentbody that allows the perfusion lumen of the venous perfusion conduit 448to be in fluid communication with the venous perfusion space 428. In theillustrated embodiment, the venous perfusion conduit extends from theinterior of the proximal end portion 4426 of the arterial perfusionstent 404 to the venous perfusion space 428, thereby allowing suchaccess.

Referring again to FIG. 13 , as noted above the arterial perfusion stent402 can include a liner 466 that is non-porous to the perfusion fluid(blood, in the illustrated embodiment). The liner can be secured to theframe 430 by any suitable means, for example an adhesive or suturing.The liner covers the frame 430 of the arterial perfusion stent andprevents or substantially reduces mixing of blood flowing through theaorta and the central lumen 403 with the perfusion fluid flowing throughthe perfusion space 416. The venous perfusion stent 404 includes anon-porous liner that can be substantially identical to the liner usedfor the arterial perfusion stent, and that prevents or substantiallyreduces mixing of blood flowing through the inferior vena cava with theperfusion fluid flowing through the perfusion space 428. However, theliners of the arterial and venous perfusion stents 402, 404 can includeminor structural differences (for example in diameter or length) asneeded for sufficient coverage of the arterial and venous perfusionstents. In the illustrated embodiment, the liner is located on theoutside of the frame of the perfusion stent. However, the liner can belocated on the stent in any way that provides a non-porous barrier toblood. For example, the liner can be located on the inside of the frameof the stent, or on both the outside and the inside of the stent.

In several embodiments, the liner 466 can be made of any suitablebio-compatible synthetic or biological material, such as those describedin U.S. Pat. No. 6,730,118, which is incorporated herein by reference.The liner 466 desirably can be substantially impermeable to aqueoussolutions, such as blood or plasma. In some embodiments, the liner 466can be a polymer or composite membrane or layer, for example,polytetrafluoroethylene (PTFE); or a woven, knit, or non-woven fabricmaterial (e.g., a ripstop fabric) manufactured from natural and/orsynthetic yarns or fibers, such as woven polyester (e.g., polyethyleneterephthalate, PET, such as Dacron®), or cellulose (such as cotton orlinen), silk, nylon, polyolefin, carbon fiber, and/or metal fibers. Inadditional embodiments, the liner 466 can be made of a synthetic and/ornatural material that is coated with a sealant (such as ePTFE,fluoropolymer, or gelatin (Vasutek® Gelatin Sealant, Terumo, UK); see,e.g., International Publication No. WO 2001/080918, which isincorporated by reference herein in its entirety). In more embodiments,the liner 466 can be made of a bio-synthetic materials and composites(e.g., collagen-polyester composites, Omniflow®, Bio Nova, Melbourne,AU). Other embodiments use natural tissue, including intestinalsubmucosa, natural blood vessels (arteries or veins, e.g., from animalsources), pericardial tissue and the like, which may be fixed (forexample, using gluteraldehyde and/or formaldehyde). Other embodimentsinclude artificial collagen or cellulose tubes.

In some embodiments, the liner 466 is manufactured from sheet stock, twoedges of which are brought together, for example, overlapped and/orabutted, and sealed or closed to form a tube comprising a seam. In someembodiments, the seam is linear, for example, extending along alongitudinal axis. In other embodiments, the seam has a different shape,for example, zig-zag or helical. The edges are closed using any suitablemethod, for example, suturing, welding, gluing, laminating, and/orbonding. In other embodiments, the liner 466 does not comprise a seam,for example, when the tubular sealing member comprises a portion of ablood vessel, intestinal submucosa, or certain artificial tubularstructures.

In additional embodiments, the liner 466 can desirably be made of anelectrospun polyurethane fabric (see, e.g., Amoroso et al., Elastomericelectrospun polyurethane scaffolds: The interrelationship betweenfabrication conditions, fiber topology, and mechanical properties.Advanced materials. 23:106-111, 2011, which is incorporated by referenceherein in its entirety). In particular embodiments, the frame 430 of thestent can comprise a micro-pattered thin Nitinol film (see, e.g.,WO2004/028340; Chun et al., Thin film nitinol microstent for aneurysmocclusion, J. Biomechanical Engineering, 131(5):051014, 8 pages, 2009;Chun et al., Novel micro-patterning processes for thin film nitivascular devices Smart Materials and Structures, 19:105021, 2010; Chunet al., Modeling and experimental analysis of the hyperelastic thin filmnitinol, Journal of Intelligent Material Systems and Structures. 22,2045-2051, 2011; Rigberg et al., Thin-film nitinol (niti): A feasibilitystudy for a novel aortic stent graft material Journal of vascularsurgery, 50:375-380, 2009; each of which is incorporated by referenceherein in its entirety). Micro-fabrication techniques can be used toform a plurality of micro-openings or apertures in a thin sheet ofNitinol (about 6 μM) so as to form a thin film lattice or mesh. A layerof non-porous material, such as polyurethane or ePTFE, can be applied toand secured to the metal film to provide the liner 466.

FIG. 17 depicts the stent 402 being deployed from a sheath 472 of adelivery apparatus. As shown, each of the perfusion stents 402, 404 caninclude suitable positioning markers and/or sensors at convenientlocations to assist in locating the proximal and distal end portions ofeach perfusion stent at the desired locations within the aorta or theinferior vena cava. For example, each of the distal end portion 410 andproximal end portion 414 of the arterial perfusion stent 402 can includea respective positioning marker 468 (see FIG. 17 ). In some embodiments,the positioning markers 468 can be radiopaque markers that can be usedto locate the position of the stent during deployment in a patient byradiography. For example, an x-ray image of the stent within the body ofthe patient can be obtained using a bed-side x-ray machine to determinethe position of the stent within the aorta or inferior vena cava.Certain bones or other tissue visible under x-ray can be used aslandmarks to help position the stent relative to the visceral arteries.For example, the radiopaque markers 468 can be positioned above andbelow the T12 and L2 vertebrae. Although the illustrated embodimentincludes a pair of positioning markers for the arterial perfusion stent,a greater or fewer number of markers can be provided as needed for thesurgeon to properly position the stent in the aorta of the patient. Thedistal end portion 422 and proximal end portion 426 of the venousperfusion stent 404 similarly can include a corresponding pair ofradiopaque markers that can be used to position the venous perfusionstent in a patient by radiography.

In an alternative embodiment, positioning markers 468 can be provided onthe sheath 472. When the stent 402 is located in the sheath, one markeris aligned with the distal end portion 410 of the stent and the othermarker is aligned with the proximal end portion 414.

In alternative embodiments, the positioning markers can comprise passiveor active emitters that can emit electromagnetic waves through the bodyand a corresponding detector or monitor can be used to receive theelectromagnetic waves from the emitters and provide visual and/oraudible feedback to a user indicating the position of the markers insidethe body relative to external landmarks on the body. In particularembodiments, for example, the positioning markers can be emitters thatcan emit radiofrequency waves, such as radiofrequency identification(RFID) tags. Further details of the use of RFID tags as positioningmarks are disclosed in co-pending Application No. 61/845,896, filed Jul.12, 2013, which is incorporated herein by reference.

Referring to FIG. 11 , the arterial and venous perfusion stents can besecured to respective one or more recovery wires 470. The recovery wires470 can be secured to the proximal end of the frame of the perfusionstents and can extend proximally from the perfusion stents to outsidethe patient's body via the artery or vein through which the perfusionstent was deployed. If it is desired to re-position or remove thearterial and/or venous perfusion stents from the patient (for example,if the patient recovers), then tension can be applied to the recoverywires to retract the perfusion stents in the proximal direction intorespective sheaths 472. Once the stents are retracted into the sheaths472, the sheaths can be withdrawn from the body. The tapered sections411 b, 415 b of the end portion of the stent facilitate recapture of thestent back into the sheath 472.

In use, as depicted in FIG. 10 , the arterial perfusion stent 402 can beinserted into the aorta via an incision in a femoral artery in aminimally invasive manner using known techniques. Similarly, the venousperfusion stent 404 can be inserted into the inferior vena cava via anincision in a femoral vein in a minimally invasive manner Guidewires,dilators and/or introducers can be used to help introduce and advancethe perfusion stents through the patient's vasculature, as known in theart. As best shown in FIG. 11 , the arterial perfusion stent ispositioned such that the distal end portion 410 is upstream of thevisceral arteries 80 and the proximal end portion 414 is positioneddownstream of the visceral arteries 80. Similarly, the venous perfusionstent 404 is positioned such that the distal end portion 422 ispositioned downstream of the visceral veins 84 and the proximal endportion 426 is positioned upstream of the visceral veins 84. The properpositioning of the perfusion stent 402, 404 can be accomplished byviewing the markers 468 by x-ray or under fluoroscopy, for example.

Once the arterial and venous perfusion stents are in place, the proximaland distal end portions of each stent form a seal against the innerwalls of the aorta and inferior vena cava, respectively, therebyisolating blood flow from the aorta 82 to the visceral arteries 80 andfrom the visceral veins 84 to the inferior vena cava 86. Thus, bloodfrom the heart can flow through the arterial stent 402 (bypassing thevisceral arteries), through the vasculature of the lower extremities,through the venous stent 404 (bypassing the visceral veins), and back tothe heart. The blood flow to and from the visceral organs is redirectedfrom the venous perfusion space 428 around the venous perfusion stent404 through the venous perfusion conduit 448 and via the catheter 464 tothe blood pump 460, blood oxygenator and/or warmer 458 that are outsidethe patient's body. The blood is then redirected back into the patientvia the catheter 456 connected to the arterial perfusion conduit 446 andinto the arterial perfusion space 416 around the arterial perfusionstent 402. The blood flows through the visceral arteries 80 to theabdominal organs, and back to venous perfusion space 428 via thevisceral veins 84.

Although perfusion with the patient's blood is discussed above, use of acold perfusion fluid is also available. The cold perfusion fluid can beintroduced into the arterial perfusion space 416 via the arterialperfusion conduit 446, and retrieved from the venous perfusion space viathe venous perfusion conduit 448 similar to that shown in FIG. 2 .

In particular embodiments, the perfusion fluid can be similar to theUniversity of Wisconsin solution and can comprise, without limitation,one or more of the following compounds: heparin, pentastarch, steroids,lactobionic acid, magnesium sulfate, raffinose, adenosine, allopurinol,glutathione, and potassium hydroxide. The perfusion fluid can be cooledto a temperature of about 0 degree C. to about 10 degrees C. forintroduction into the body and more preferably to a temperature of about4 degrees C. to about 6 degrees C. As an alternative perfusion fluid,blood separate from the circuit of blood being circulated by the heartcan be propelled, oxygenated and warmed before being cycled continuouslythrough the catheters, as further described below.

The apparatus 400 is particularly suited for use with DCD donors. Inthis regard, the perfusion stent 402, 404 can be inserted and deployedin the vasculature of a DCD donor as soon as possible prior to cardiacdeath. For example, the perfusion stent 402, 404 can be inserted anddeployed in a DCD donor just prior to or at the same time as removingthe patient from life support or when the donor is experiencing unstablevital signs for normal organ blood flow. The blood flow circuit allowsfor normal blood flow through the body, except for those isolatedregions, while awaiting expected cardiac death and during thepredetermined waiting period before explant can occur. In anotherimplementation, the perfusion stents 402, 404 can be inserted into theDCD donor prior to cardiac death and then are deployed at the time ofcardiac death. In yet another implementation, the apparatus can beinserted and deployed in a donor who expires prematurely before a donorteam is ready to perform the explant procedure. In any case, during theperiod of time before explant can be performed, the perfusion fluidreduces warm ischemia time and preserves organ function.

FIG. 18 shows an endovascular apparatus 600, according to anotherembodiment. The endovascular apparatus 600 is similar in many respectsto the apparatus 400 of FIGS. 10 and 11 , but has been modified fordeployment in the aortic arch and superior vena cava to isolate andperfuse the head and arms of a patient with a perfusion fluid.

The apparatus 600 in the illustrated embodiment comprises an arterialperfusion stent 602 and a venous perfusion stent (not pictured). Thearterial perfusion stent 602 is configured for deployment in the aorticarch and to isolate blood to the head and arms via carotid andsubclavian arteries 601. When deployed in a patient, the endovascularapparatus 600 allows blood from the heart to pass uninterrupted througha central lumen of the arterial perfusion stent 602 and flow via theaorta 82 to perfuse the abdomen and lower body and then flowuninterrupted through the inferior vena cava to return to the heart.Further, the arterial perfusion stent 602 of endovascular apparatus 600is configured to introduce a perfusion fluid (e.g., re-oxygenated and/orwarmed blood) into the carotid and subclavian arteries 601 for thepurpose of perfusing the head and arms with the perfusion fluid. Forexample, the apparatus 600 can be used to maintain blood flow to thebrain or spinal cord during a surgical procedure that restricts suchflow in order to reduce or prevent brain ischemia or spinal cordischemia during the procedure.

The arterial perfusion stent 602 can have a similar construction as thatof the arterial perfusion stent 402. The size and shape of the arterialperfusion stent 602 can be generally similar to the size and shape ofthe arterial perfusion stent 402, with modifications as needed to allowfor deployment of the arterial perfusion stent 602 in the aortic arch.For example, similar to arterial perfusion stent 402, the arterialperfusion stent 602 comprises an elongated body that includes an annularframe supporting a non-porous liner that can be radially compressible toa compressed state for delivery through the body to a deployment siteand expandable to its functional size shown in FIG. 18 at the deploymentsite. Similar to perfusion stent 402, the perfusion stent 602 can beself-expanding, or, in other embodiments, can be aplastically-expandable perfusion stent. The frame and the non-porousliner of the arterial perfusion stent 602 can be made of the samematerials as those used for the arterial perfusion stent 402.

The stent 602 defines a central lumen that extends from a proximal end608 to a distal end 606 of the perfusion stent. The central lumen allowspassage of fluid (e.g., blood) through the body of the perfusion stent,thus maintaining blood flow through the artery in which the perfusionstent is deployed. In the radially expanded state of the perfusionstent, distal and proximal end portions 610, 614 have an outer diameterthat is larger than the outer diameter of an intermediate portion 612,thereby defining an annular perfusion space 616 between the end portionsand around the intermediate portion. The outer surfaces of the distaland proximal end portions 610, 614 form a seal against the inner wall ofthe aorta when the arterial perfusion stent is in the radially expandedstate.

Similar to the arterial perfusion stent 402, the arterial stent 602 cancomprise a perfusion lumen (such as defined by an arterial perfusionconduit or sleeve 646) that is in fluid communication with the arterialperfusion space 616 and facilitates perfusion of blood or fluid throughthe head and arms, while allowing normal blood flow between the heartand lower extremities. The perfusion fluid can flow through theperfusion lumen and into the arterial perfusion space 416. The arterialperfusion conduit 646 can extend at least partially through the proximalend portion 614 of the stent body and has a proximal end that can extendbeyond the proximal end portion 614, where it can be fluidly connectedto a catheter that extends outside of the body of the patient.Desirably, the catheter can be connected to an oxygenator and/or bloodwarmer and/or a blood pump to treat and pump the blood of the patient asneeded.

The venous perfusion stent included in the apparatus 600 can beconfigured for deployment in the superior vena cava to isolate bloodflow returning from the head and arms to the heart via the superior venacava. The venous perfusion stent is configured to receive the perfusionfluid from the superior vena cava that was introduced into the body fromthe arterial perfusion stent 602. The venous perfusion stent ofapparatus 600 can have a structure similar to the venous perfusion stentof apparatus 400, and can be configured for placement in the superiorvena cava in any way so as to collect fluid returning via the superiorvena cava to the heart. In some non-limiting embodiments the venousstent can include a configuration such that a perfusion space of thestent collects fluid (e.g., blood) from the right brachiocephalic vein,the left internal jugular, or the right brachiocephalic vein and theleft internal jugular.

Once the arterial and venous perfusion stents of the apparatus 600 arein place, the proximal and distal end portions of each stent form a sealagainst the inner walls of the aortic arch and superior vena cava,respectively, thereby isolating blood flow from the aorta to the carotidand subclavian arteries 601 and from the veins of the head and arms tothe superior vena cava. Thus, blood flow to and from the head and armsis redirected from the superior vena cava through a venous perfusionconduit to a blood pump, blood oxygenator and/or warmer that are outsidethe patient's body. The blood is then redirected back into the patientvia the catheter 646 connected to the arterial perfusion conduit 646 andinto the arterial perfusion space 616 around the arterial perfusionstent 602. The blood flows through the carotid and subclavian arteries601 to the head and arms, and back to superior vena cava.

The embodiments disclosed herein can be used for procedures other thanprocedures for preserving organ function for explant surgery. Forexample, in another implementation, an endovascular apparatus (e.g., anapparatus of FIG. 1, 5, 6, 10, 11, 12 , or 18) can be used to perfuseorgans during survival surgery, such as cardiac or proximal aorticrepairs where prolonged cessation of blood flow poses a risk of organdamage. In another implementation, an endovascular apparatus (e.g., anapparatus of FIG. 1, 5, 6, 10, 11, 12 , or 18) can be used toselectively perfuse organs, but not other body regions, with atherapeutic agent. For example, if a particular therapeutic agent hastherapeutic effect on the organs, but is toxic to other body regions(for example, the central nervous system), the agent can be selectivelyadministered to the organs using a disclosed endovascular apparatus. Inone non-limiting example, a chemotherapeutic agent can be delivered tothe visceral organs using a disclosed endovascular apparatus (e.g., anapparatus of FIG. 1, 5, 6, 10, 11 , or 12) to selectively perfusion thevisceral organs of the body with a solution (e.g., blood) that includesthe chemotherapeutic agent.

GENERAL CONSIDERATIONS

For purposes of this description, certain aspects, advantages, and novelfeatures of the embodiments of this disclosure are described herein. Thedisclosed methods, apparatuses, and systems should not be construed aslimiting in any way. Instead, the present disclosure is directed towardall novel and nonobvious features and aspects of the various disclosedembodiments, alone and in various combinations and sub-combinations withone another. The methods, apparatuses, and systems are not limited toany specific aspect or feature or combination thereof, nor do thedisclosed embodiments require that any one or more specific advantagesbe present or problems be solved.

Although the operations of some of the disclosed methods are describedin a particular, sequential order for convenient presentation, it shouldbe understood that this manner of description encompasses rearrangement,unless a particular ordering is required by specific language. Forexample, operations described sequentially may in some cases berearranged or performed concurrently. Moreover, for the sake ofsimplicity, the attached figures may not show the various ways in whichthe disclosed methods can be used in conjunction with other methods. Asused herein, the terms “a”, “an” and “at least one” encompass one ormore of the specified element. That is, if two of a particular elementare present, one of these elements is also present and thus “an” elementis present. The terms “a plurality of” and “plural” mean two or more ofthe specified element.

As used herein, the term “and/or” used between the last two of a list ofelements means any one or more of the listed elements. For example, thephrase “A, B, and/or C” means “A,” “B,” “C,” “A and B,” “A and C,” “Band C” or “A, B and C.”

As used herein, the term “coupled” generally means physically coupled orlinked and does not exclude the presence of intermediate elementsbetween the coupled items absent specific contrary language.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. We thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

We claim:
 1. A perfusion stent implantable within a body lumen, thestent comprising: a radially compressible and expandable, elongated bodycomprising first and second end portions and an intermediate portionextending from the first end portion to the second end portion; thefirst and second end portions having an outer diameter greater than anouter diameter of the intermediate portion when the body is in aradially expanded state, thereby defining an annular perfusion spacebetween the first and second end portions and around the intermediateportion, wherein the first and second end portions comprise acylindrical first section and a tapered second section positionedproximal to the first section when in the radially expanded state; acentral lumen extending through the first end portion, the intermediateportion, and the second end portion; and a perfusion lumen extending atleast partially through the first end portion and having a distalopening in communication with the perfusion space; wherein when theelongated body is in the radially expanded state within the body lumenand the first and second end portions are engaged with an inner wall ofthe body lumen, the central lumen is fluidly separated from theperfusion space, and wherein a proximal end of the elongated body isconnected to a recovery wire.
 2. The perfusion stent of claim 1, furthercomprising a retractable sheath.
 3. The perfusion stent of claim 1,wherein the elongated body comprises a self-expandable frame.
 4. Theperfusion stent of claim 1, further comprising a perfusion conduitextending at least partially through the first end portion, theperfusion conduit defining the perfusion lumen.
 5. The perfusion stentof claim 1, wherein the elongated body comprises an inlet and an outletof the central lumen and a surface that is non-porous to bloodsurrounding the central lumen and extending longitudinally from theinlet to the outlet.
 6. The perfusion stent of claim 3, wherein theelongated body comprises a liner attached to the self-expandable frame,the liner defining the surface that is non-porous to blood.
 7. Theperfusion stent of claim 3, wherein the self-expandable frame of thefirst and second end portions comprises angled struts.
 8. The perfusionstent of claim 6, wherein the self-expandable frame comprises amicropatterned Nitinol film and the liner comprises polymeric film. 9.The perfusion stent of claim 6, wherein the liner is secured to theself-expandable frame by an adhesive or suturing.
 10. The perfusionstent of claim 6, wherein the liner is located outside of theself-expandable frame, inside of the self-expandable frame, or on boththe outside and inside of the self-expandable frame.
 11. The perfusionstent of claim 1, wherein the first and second end portions comprise apositioning marker.
 12. The perfusion stent of claim 11, wherein thepositioning marker is a radiopaque marker.
 13. The perfusion stent ofclaim 11, wherein the positioning marker comprises a passive or activeelectromagnetic wave emitter.
 14. A method of selectively administeringa therapeutic agent to an organ of a subject comprising implantingwithin a body lumen the perfusion stent of claim
 1. 15. The method ofclaim 14, wherein the organ is a visceral organ.
 16. The method of claim14, wherein the therapeutic agent is a chemotherapeutic agent.
 17. Themethod of claim 14, wherein the therapeutic agent is toxic to thecentral nervous system of the subject.
 18. The method of claim 14,wherein the method comprises perfusing the organ with a solution. 19.The method of claim 18, wherein the solution is blood.